1. Field of the Invention
The present invention relates to a digital information reproducing apparatus and digital information distributing system. More particularly, this invention is concerned with a digital information reproducing apparatus and digital information distributing system that employ a semiconductor memory as a digital information storage medium, store digital information in a compressed and thus encoded state, and decode and reproduce the digital information.
2. Description of the Related Art
A digital information reproducing apparatus in accordance with a prior art which employs a semiconductor memory is, for example, described in Japanese Unexamined Patent Publication No. 3-139700. FIG. 10 is a functional block diagram showing the outline configuration of a compact musical signal reproducing apparatus described in the patent publication.
As shown in FIG. 10, a compact musical signal reproducing apparatus 40 in accordance with the prior art has a semiconductor memory 41, decoding circuit 42, D/A converter 43, and headphone unit 44 incorporated therein.
In the semiconductor memory 41, musical digital data that has been encoded highly efficiently by an encoding circuit 33 is stored in advance. As stages preceding the encoding circuit 33, an input terminal 31 and an A/D converter 32 are installed. A musical analog signal supplied through the input terminal 31 is converted into a digital signal by the A/D converter 32 and supplied to the encoding circuit 33.
The musical digital data stored in the semiconductor memory 41 is decoded by the decoding circuit 42 in the apparatus 40, and thus restored to an original musical digital signal. The digital signal is then converted into an analog electric signal by the D/A converter 43, and converted into an acoustic signal by the headphone unit 44. Eventually, music is output.
However, in the foregoing digital information reproducing apparatus of the prior art, the specified decoding circuit that has been incorporated in the course of manufacturing is used to decode data. Data that has been compressed and thus encoded in a different coding form cannot be reproduced at all. Thus, a problem of software incompatibility occurs.